[plug] Unresolved module references

[Ian Kent]

On Thu, 17 Jun 2004, Cameron Patrick wrote:

> raven at themaw.net wrote:
> 
> | > FWIW I've often got "unresolved references" in one or two modules and
> | > had no idea what caused it.  The modules in question still loaded
> | > properly with insmod, just depmod complained.  The last few kernels
> | > that I've built seem to have been okay in this regard, but I've no
> | > idea why...  i.e. I'd like an answer to what causes this too :-)
> | > 
> | 
> | Well the cause is clear enough. The symbol refered to is not being
> | exported in the source. This can be due to errors in patch sets, just 
> | plain errors in kernel source or defining code that is not included due to 
> | a config option.
> 
> Maybe... but if the symbols /really/ weren't being exported by the
> kernel, why did the modules insmod properly?  I think you're right
> that it was due to something screwy going on when compiling the kernel
> though.
> 

I must admit I thought insmod would barf but clearly not.

Just because the symbol is not available doesn't mean the module won't 
work. However it may fail in an unexpected way one day.

It's easy enough to check if the symbol is actually exported by the kernel 
(or another module). Look for EXPORT_SYMBOL or EXPORT_SYMBOL_GPL. You 
should get some hint as to the directory tree to search from your 
messages.

Ian